Sustainability Indicators Board Meeting & Workshop July 25, - PowerPoint PPT Presentation

Sustainability Indicators Board Meeting & Workshop July 25, 2019

S ustainability Indicators  S ustainability indicators are the effects caused by groundwater conditions occurring throughout the basin that, when significant and unreasonable, become undesirable results

Chronic Lowering of Groundwater Levels  S ignificant and unreasonable depletion of groundwater supply if continued over the next 50 years Note: this is a simplified unconfined aquifer example

North Fork Kings GS A – GW Level

S eawater Intrusion  S ignificant and unreasonable seawater intrusion  Effects overlying land uses and direct use of groundwater  Not applicable in S anta Margarita Basin

Degraded Groundwater Quality  S ignificant and unreasonable degraded groundwater quality caused by proj ects and management actions  This is a “ do no harm” indicator – not required to address existing groundwater quality issues but cannot cause them to get worse  Including the migration of contaminant plumes that impair water supplies

Land S ubsidence  S ignificant and unreasonable land subsidence caused by changes in groundwater levels that substantially interferes with surface land uses  Not applicable in S anta Margarita Basin

Depletion of Interconnected S urface Water  Depletions of interconnected surface water caused by use of groundwater that have significant and unreasonable adverse impacts on beneficial uses of the surface water

Groundwater / S urface Water Interactions

Mid-County Groundwater Level Near Creek

Mid-County Groundwater Level Near Creek

Reduction of Groundwater in S torage  S ignificant and unreasonable groundwater extractions from the basin that may lead to undesirable results  Must be supported by the Basin sustainable yield

Mid-County Change in S torage

Iterative Process Groundwater Basin Conditions Model GS P Preliminary Minimum Thresholds Terminology & Concepts Proj ects & Management Actions Impact Assessment (Modeling) Finalize Measureable Obj ectives & Interim Milestones Finalize Proj ects & Management Actions Refine Minimum Thresholds Impact Assessment (Modeling) Refine Proj ects & Management Action Draft Measureable Obj ectives & Interim Milestones Impact Assessment (Modeling) Finalize Minimum Thresholds Repeat as Needed

S ustainable Management Criteria  GS As must consider and document the conditions at which the 6 sustainability indicators become “ significant and unreasonable” in their Basin,  These descriptions of significant and unreasonable conditions are later translated into quantitative “ undesirable results” .  S ignificant and unreasonable conditions must be evaluated and monitored to determine “ minimum thresholds”  A “ minimum threshold “ is the quantitative value for a representative monitoring site that, when exceeded individually or in combination with minimum thresholds at other monitoring sites, may cause an undesirable result(s) in the basin.  GS As need to set minimum thresholds at representative monitoring sites for each applicable sustainability indicator AFTER considering the interests of beneficial uses and users.

Undesirable Results –An Iterative Approach